CustomScheme Object 
- schemestring - Custom schemes to be registered with options.
- privilegesObject (optional)- standardboolean (optional) - Default false.
- secureboolean (optional) - Default false.
- bypassCSPboolean (optional) - Default false.
- allowServiceWorkersboolean (optional) - Default false.
- supportFetchAPIboolean (optional) - Default false.
- corsEnabledboolean (optional) - Default false.
- streamboolean (optional) - Default false.
- codeCacheboolean (optional) - Enable V8 code cache for the scheme, only works when- standardis also set to true. Default false.